Selector switch



March 1, 1932. G. w. FOLKNER 1,847,213

SELECTOR SWITCH Filed April 28, 1931 0. wrouwm BY @am.

A T TORNE Y Patented Mar. 1, 1932 UNITED STATES PATENT OFFICE GEORGE W.FOLKNER, OF MAPLEWOOD, NEW JERSEY, ASSIGNOR TO BELL TELEPHONELABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK Application filed April 28,

This invention relates to switching apparatus for use in automatic andsemi-automatic systems, and more particularly to a panel switch of themulti-brush type, that is, a switch provided with a plurality ofbrushsets any one of which may be rendered operative in extending acall.

The principal object of this invention resides in the provision ofimproved means for tripping or rendering operative any desired one ofthe brush-sets of a switch. At the present time, in switches of thistype, a brush selecting or tripping rod is provided which is adapted toengage the lever of the desired brush-set for releasing the associatedbrushes and allow them, upon movement of the brush shaft, to traversethe stationary terminal section with which the brushes cooperate,

while the other sets of brushes remain in their inoperative position butmove with the shaft. The invention contemplated herein has to do withproviding a new and novel tripping device which is reliable in operationand economical to install and maintain.

Thetripping device contemplated in this invention comprises alongitudinal flexible spring and a clamp for attachment to the tripp ngrod. The base of the spring is :formed into a finger for coming intoproper 1 30 engagement with the brush releasing lever of the brush-setwhich is to be released for contact with the stationary terminalsection. The spring tripping device is of such length and material 'thatsome-deflection from its main adjustment can take place. There is onesuchv springtripping device and clamp for each brush-set,'arranged atprogressively increasing distances above the normal position of theirrespective brush controlling levers. These trip springs are so clampedto the trip rod that the lower finger normally extends slightly to oneside of the line of travel of the brush levers, means being providedwhereby the trip rod may be momentarily rotated to cause the fingers tointercept such line of travel. Thus, it will be seen that during theupward movement of the brush shaft the controlling lever of anydesiredbrush-set occupies a position below the engaging portion of itscooperating trip SELECTOR swITcH 1931. Serial no. 533,429.

finger and; in contact with it, the trip rod being momentarily rotatedto its trippin position. One of the trip fingers of the rod will engagethe lever of the desired brush-set, whereby the brush controlling leverwill be released and the brushes, by reason of the resiliency of theirsupporting arms, will assume their contacting position.

When the switch restores to normal on its downward movement, should thetrip lever of any of the brushes engage with the upper surface of thefinger of a trip sprin there is suiiicient resiliency in the body of t espring to flex edgewise and allow the switch thereafter to proceedundisturbed to its normal posltion, the trip spring snapping back to itsrigid position of rest when the lever gets out of engagement with thesaid spring.

A clearer conception of the scopeand purpose of the invention may beobtained from the following description taken in connection withthe'attached drawings in which;

Fig. 1 is a normal side view of aselector switch brush-set together withthe associated anism with the brush springs of the cooperating brush-setremoved to show one position of the brush releasing lever of saidbrushset in relation to said tripping mechanism;

Fig. 6is an enlarged perspective view of the position shown in Fig.15; pv

Fig 7 is the same as Fig. 6, except that said tripping mechanism isshown operated by said brush releasing lever in the improved mannerdescribed hereunder; and

Fig. 8 is the same as Fig. 7 except that 1' the brush tripping lever isshown clear, of the trip finger mechanism.

In Fig. 1, 1 is a brush frame carrying an assembly of brush springs,said brush frame being attached, to the selector switch rod 2. The triprod is indicated by 3, to which a tripping mechanism is attached foreach brush-set on the selector switch. A selector switch of this generalcharacter is described in Patent No. 1,123,696, granted on January 15,1915, to E. B. Craft and J. N. Reynolds and is not further described inthis specilieation except insofar as it aids in a clearer understandingof the present invention. For any further description of the saidsclector switch, reference is made to the said patent.

The physical structure of the invention under consideration may be mostreadily understood by a consideration of Fig. 6. To the trip rod 3 aclamp 5 is attached. The clamp is shown in detail in Fig. 4 and is madeof any suitable material, such as brass, and has two free ends. The leftend 12 e):- tends outwardly and then downwardly and terminates in ahorizontal triangular projection 13. Through the upper portion of saidleft free end and through the corresponding portion of said right freeend, aligned holes are provided for the reception of a clamping bolt 6.The said left free end is further provided with a rectangular slot 11for the reception of the tripping spring as more clearly set forthhereinafter.

A longitudinal tripping spring a for attachment to said clamp is shownin Fig. 3. It is substantially U-shaped, having an arm 15 with arectangular central portion for cooperation with the left free end ofclamp 5, and having a hole centrally located therein for the passage ofthe clamping bolt 6. The left arm 15 of said spring terminates in asmall rectangular horizontal lip 16 for engagement in slot 11 of theclamp 5. The arm 4 of the spring parallels the left arm 15 for adistance below the bolt hole and then curves sharply toward thelongitudinal cen ter at 17 until it reaches a point approximately underthe edge of lip 16, where it sharply bends vertically downward for theremainder of its length. The end of arm 4; of the spring comprises arear oblique flange 14 and the front trip finger 9 and sup sortingflange 18 for said linger.

In the assembly of the tripping mechanism the clamp 5 is first attachedto the trip rod 3 and the spring is then attached by its left arm 15 tothe left free end 12 of said clamp by bringing into engagement lip 16with the registering slot 11 and causing the hole in the left arm ofsaid spring to register with the bolt holes in said clamp. The locationof slot 11 of the clamp, therefore, must de pend upon the length andstructural determination of the left arm 15 of said spring. Bolt 6 isthen passed through the registering holes and the clamp and spring areclamped tightly to each other and to the trip rod 3 by nut 7 threadedonto the end of said bolt.

When the spring is thus assembled to said clamp and rod, flange 14:rests against the surface of the rod, the finger 9 is below thetriangular projection 13 of the clamp while the lower part of arm 4 ofthe spring is between said triangular projection and said rod, therebeing sufficient clearance at either end to permit the spring to movefreely between said projection 13 and said rod. If the spring, when soassembled, is given a downward or backward thrust, said thrust istransmitted to flange 1 1 which is in sliding contact with the rod. Thebackward motion which the spring would have under such circumstances, istranslated into a sideways motion by the flange sliding along thesurface of the rod and thereby causing the right arm l of the trippingspring and therefore finger 9 to be deflected to the right.

In the normal position of a. trip finger of an associated bruslrsetwhich is not to be tripped in the upward movementof the se lector, thetripping lever 10 of said brush-set clears the left edge of finger 9 ofthe said tripping linger. In. accordance with the operation described inthe above mentioned patent, when a particular brush-set is to betripped, the selector is moved upwards until the inclined edge 20 oflever 10 of the brush releasing mechanism of the brush-set to be trippedis brought directly underneath the finger 9 of the cooperating tripmechanism. The trip rod is then rotated to the right and surface 20 islocked under the linger 9 and supporting flange 18. The next forwardmovement of the selector causes the brush releasing mechanism controlledby lever 10 to be released, thereby allowing the brushes of theassociated brush assembly to engage the terminals on the bank to whichthe brushes have access. In this respect, therefore, there is nodifference between the operation of the tripping mechanism of thepresent invention and the tripping mechanisms for this type of switchdisclosed in the prior art, such as, for example, the tripping mechanismdisclosed in the above mentioned patent.

Then the selector restores to normal, the brush lever 10 of each brushnot tripped clears to the left of finger 9. It happens, however, thatsometimes, due to faulty adjustments, the lever 10 of the brushreleasing mechanism of some of the normal brush-sets in the selectordoes not clear the linger 9 but will snag with its base directly on topof it during the downward motion of the selector as more particularlyshown in Figs. 5 and 6. If the trip finger is rigid, both the brush-setand the tripping mechanism of the snagging brush may be damaged. WViththe tripping mechanism of my invention, however, when such a conditionexists, the downward thrust of the lever 10 will push the arm 4 of thespring inwardly. The pressure is communicated to flange 14; and thebackward motion imparted to the spring by the downward thrust of the Illlever 10 will change the backward movement of the sprin to a sidewaysmovement as already descri ed. Under such circumstances, the springyields sideways and is pushed aside until the right edge of lever 10clears the edge of the finger 9 as shown in Fig. 7. The brush lever 10is then free from the obstruction caused by the snagging and willcontinue its downward motion until the selector comes to rest. When thelever 10 has completel cleared the spring finger, the spring will exback into its normal position and is then ready for service again.

By providing a tripping mechanism which can be thrust aside by asnagging brush on the downward movement of the selector, the brushreleasing mechanism is saved from injury, while the resiliency of thespring will always cause the finger to be flexed back to its normalposition for normal operation.

What is claimed is:

1. In a switch, a movable selector shaft, a plurality of brush-sets, abrush releasing mechanism for each brush-set, and a cooperating devicefor operating each of said mechanisms comprising a flexible member, saidmember operating one of said brush releasing mechanisms when saidselector shaft moves in one direction and flexing edgewise when one ofsaid mechanisms engages said member when said selector shaft moves inthe opposite direction.

2. In a switch, a shaft longitudinally movable in an operating and in arestoring movement, a plurality of brushes secured thereto, means fornormally retaining said brushes in an inoperative position, and arotatable device common to said brushes comprising a flexible springmember for selectively tripping one of said brushes, said spring memberbeing arranged to flex edgewise when said means for normally retainingsaid brushes in inoperative position engages said spring member in therestoring movement of said shaft.

3. In a switch, a shaft longitudinally movable in an operating and in arestoring movement, a plurality of brush-sets secured thereto, acontrolling means for each set normally holding the brushes thereofspaced in an inoperative position and a tripplng device common to saidbrush-sets comprising a plurality of flexible spring members, each ofsaid spring members being adapted for selectively tripping a specificone of said brush-sets whereby each of said spring members is alsoadapted to flex edgewise when any of said controlling means engages anyof said spring members in the restoring movement of said shaft.

4. In a switch, a shaft longitudinally movable in an operatin and in arestoring movement, a plurality o brush-sets secured thereto, amechanism for each brush set movable therewith and adapted to normallymaintain said cooperating brush-set in an inoperative position, atripping lever for each of said mechanisms, a tripping device common tosaid brush-sets comprising a flexible spring member for each of saidbrush-sets and a finger on each of said springs at the base thereof toengage said tripping lever when the latter is stopped in juxtapositionto the position of said finger for releasing said mechanism to place thecooperating brush-set in operative position, whereby any one of said srin members flexes edgewise when one o sai tripping levers engages saidfinger in the restoring movement of said shaft.

5. In a brush tripping mechanism, a trip rod, a. U-shaped clampsurrounding said rod and having aligned openings through the armsthereof, one of the arms of said clamp extending downwardly andterminating in an angular projection and having a rectangular slot, aU-shaped spring one arm of which is provided with an opening and whichterminates in a lip, the other arm of said spring terminating in anoblique flange and in a finger which extends inwardly at right angles tosaid arm, and a clamping bolt extending through the openings in saidclamp and spring for clamping said spring and clamp to said rod with thelip of said spring in engagement with the slot of said clamp, theprojeetion of said clamp overlying the finger of said spring and saidflange in engagement with said rod.

In witness whereof, I hereunto subscribe my name this 25th day of April,1931.

GEORGE W. FOLKNER.

